'Obesity' is a clinical term used to describe excess body fat associated with increased risks to health. It can increase the risk of diseases such as type 2 diabetes, cancer and heart diseases.

Measuring obesity The most common method of measuring obesity is calculating an individual's Body Mass Index (BMI). This is calculated by dividing a person's weight measurement (in kilograms) by the square of their height (in metres). The World Health Organization uses a classification system using the BMI to define normal weight , overweight and obesity.• A BMI of less than 18.5 is defined as "underweight." • A BMI of 18.5 to 24.9 is defined as a "normal weight." • A BMI of 25 to 29.9 is defined as a "overweight." • A BMI of 30 to 34.9 is defined as "obese class I." • A BMI of 35 to 39.9 is defined as "obese class II."• A BMI of or greater than 40.00 is defined as "obese class III."

The cut-offs for asian people are lower because they have much more fat within abdomen which proved to increase the risk of heart diseases and diabetes. So , Asian people are classified according to BMI as follows :• Normal weight : BMI between 18.5-23.9 .• Over weight : BMI between 24-26.9 .• Obese class I : BMI between 27-31.9 .• Obese class II : BMI between 32-36.9.• Obese class III : BMI greater than 37.The waist circumference should be no more than 102cm (men) or 88cm (women), with stricter targets for Asians of less than 90cm (men) and 80cm (women).

Impact of obesityCompared with a healthy weight man, an obese man is:• five times more likely to develop type 2 diabetes• three times more likely to develop cancer of the colon• more than two and a half times more likely to develop high blood pressure – a major risk factor for stroke and heart disease

An obese woman, compared with a healthy weight woman, is:• almost 13 times more likely to develop type 2 diabetes• more than four times more likely to develop high blood pressure• more than three times more likely to have a heart attackPsychologically, being overweight can affect the body image and damage self-esteem. In some cases this can cause social anxiety and depression.

The following medical conditions are also more common in obese people than in those of normal weight:• osteoarthritis• high cholesterol • Cardiovascular diseases• Obstructive sleep apnea• Fatty liver.

How is obesity treated?Dietary changesfollowing low-caloric diet and shifting to healthier food that contains less fat and carbohydrates .

Exercise and activitywith aim for at least 150 minutes of moderately intense exercise each week (ideally 30 minutes at least 5 days a week).

Medicationsweight-loss medication is meant to be used along with diet, and exercise , not instead of them. Medications may be indicated if:．Other methods of weight loss haven't worked．Body mass index (BMI) is 30 or greater．Body mass index (BMI) is greater than 27 with medical complications of obesity, such as diabetes, high blood pressure.

Weight-loss surgeryeven though recommended , most therapies have not been successful in keeping sustained weight loss , and controlling obesity related diseases . until now, only bariatric surgery has proven to result in effective and durable weight loss , and resolution or improvement in obesity related diseases .